Jerry,
I'm certain you really know your stuff when it comes to lubrication. I would however like to respectfully submit, that you might want to look into the cast iron porosity matter before making a blanket statement. No, it isn't a sponge as I used in my analogy, but it will and does absorb some types of
oil and solvents. I can't tell you what level of saturation occurs with each, but it does occur however minutely. Again, ask any good welder who works with repairing cast iron.
Having done precision machine work, I'm quite familiar with the finish level gauging process and have a set of gauges for the purpose. Where "x" is the value relative to a perfect mirror finish.
Al